Genetic sampling identifies canid predators of koalas (Phascolarctos cinereus) in peri-urban areas

An understanding of the threats to threatened species in urban and peri-urban areas is essential to develop successful management approaches. Dog attacks are considered to be a major contributor to koala (Phascolarctos cinereus) mortalities in peri-urban areas of north-eastern Australia. Predation could be due to either domestic dogs or wild dogs (dingoes and dingo-domestic dog hybrids), gentically-identifiable groups of Canis familiaris. Here, we aimed to use genetic sampling methods to determine or verify the identity, number and successful removal of canid predators of koalas in a peri-urban environment in south-eastern Queensland. Genetic samples were taken from the remains of 12 koalas suspected to have died from predation. Canine genotypes were present on 11 of 12 predated koalas (∼92%) and were from wild dogs, not domestic dogs. Most koalas had only one canine genotype identified, suggesting they were killed by a single dog. Our results show that DNA samples collected from deceased prey species can be used to identify the predator, and distinguish between closely-related species, and hybrids of the two. Genetic methods confirmed the identification of the predator obtained through conventional necropsy and support growing evidence that wild dog predation is a significant cause of koala mortality in this region. Strategies to reduce predation on koalas should therefore focus on reducing the impact of free-ranging wild dog populations. This approach is important to identify and target those canids responsible for predation of threatened prey populations, particularly where multiple predators are present and/or predator removals may be controversial.